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IWM vs. UNG
Performance
Return for Risk
Drawdowns
Volatility
Dividends

IWM vs. UNG

Last updated Jun 9, 2026

IWM (iShares Russell 2000 ETF) and UNG (United States Natural Gas Fund LP) are both exchange-traded funds - IWM is a Small Cap Blend Equities fund tracking the Russell 2000 Index, while UNG is a Oil & Gas fund tracking the Front Month Natural Gas. Both are passively managed. Over the past 10 years, IWM returned 10.78%/yr vs -21.26%/yr for UNG. At a 0.04 correlation, their price movements are largely independent. IWM charges 0.19%/yr vs 1.28%/yr for UNG.

Performance

IWM vs. UNG - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in iShares Russell 2000 ETF (IWM) and United States Natural Gas Fund LP (UNG). The values are adjusted to include any dividend payments, if applicable.

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Returns By Period

In the year-to-date period, IWM achieves a 15.62% return, which is significantly higher than UNG's -7.26% return. Over the past 10 years, IWM has outperformed UNG with an annualized return of 10.78%, while UNG has yielded a comparatively lower -21.26% annualized return.

IWM

1D
0.87%
1M
-0.02%
YTD
15.62%
6M
13.83%
1Y
35.52%
3Y*
16.64%
5Y*
5.48%
10Y*
10.78%

UNG

1D
-2.57%
1M
7.57%
YTD
-7.26%
6M
-24.55%
1Y
-33.82%
3Y*
-22.97%
5Y*
-23.84%
10Y*
-21.26%
*Multi-year figures are annualized to reflect compound growth (CAGR)

IWM vs. UNG - Yearly Performance Comparison

2026 (YTD)202520242023202220212020201920182017
IWM
iShares Russell 2000 ETF		15.62%12.66%11.38%16.83%-20.48%14.54%20.03%25.39%-11.12%14.58%
UNG
United States Natural Gas Fund LP		-7.26%-27.07%-17.11%-64.04%12.89%35.76%-45.43%-31.77%5.96%-37.58%

Correlation

The correlation between IWM and UNG is -0.27, meaning they tend to move in opposite directions. This is especially valuable for risk management - when one declines, the other has historically tended to hold steady or rise.

Correlation
Correlation (1Y)
Calculated over the trailing 1-year period

-0.27

Correlation (3Y)
Calculated over the trailing 3-year period

-0.07

Correlation (5Y)
Calculated over the trailing 5-year period

0.03

Correlation (10Y)
Calculated over the trailing 10-year period

0.04

Correlation (All Time)
Calculated using the full available price history since Apr 19, 2007

0.04

The correlation between IWM and UNG shifts across timeframes, from -0.27 (1 year) to 0.04 (all time), reflecting how their relationship changes across market environments.

Compare stocks, funds, or ETFs

Search for stocks, ETFs, and funds for a quick comparison or use the comparison tool for more options.

iShares Russell 2000 ETF

United States Natural Gas Fund LP

Often compared with IWM:
IWM vs. SPYIWM vs. VTWOIWM vs. IJRIWM vs. AVUVIWM vs. IWNIWM vs. VOOIWM vs. IWO
Often compared with UNG:
UNG vs. BOILUNG vs. FCGUNG vs. UNLUNG vs. LNGUNG vs. BNOUNG vs. WEATUNG vs. KOLD

Return for Risk

IWM vs. UNG — Risk / Return Rank

Compare risk-adjusted metric ranks to identify better-performing investments over the past 12 months.
IWM
IWM Risk / Return Rank: 6363
Overall Rank
IWM Sharpe Ratio Rank: 6161
Sharpe Ratio Rank
IWM Sortino Ratio Rank: 6060
Sortino Ratio Rank
IWM Omega Ratio Rank: 5454
Omega Ratio Rank
IWM Calmar Ratio Rank: 7171
Calmar Ratio Rank
IWM Martin Ratio Rank: 6868
Martin Ratio Rank
UNG
UNG Risk / Return Rank: 44
Overall Rank
UNG Sharpe Ratio Rank: 55
Sharpe Ratio Rank
UNG Sortino Ratio Rank: 55
Sortino Ratio Rank
UNG Omega Ratio Rank: 55
Omega Ratio Rank
UNG Calmar Ratio Rank: 22
Calmar Ratio Rank
UNG Martin Ratio Rank: 44
Martin Ratio Rank
The rank (0–100) shows how this investment's returns compare to the risk taken. Higher = better. Based on the past 12 months of data, combining Sharpe, Sortino, and other metrics used by quantitative funds and institutional investors.

IWM vs. UNG - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for iShares Russell 2000 ETF (IWM) and United States Natural Gas Fund LP (UNG). Risk-adjusted metrics are performance indicators that assess an investment's returns in relation to its risk, enabling a more accurate comparison of different investment options.

IWMUNGDifference
Sharpe ratioReturn per unit of total volatility
1.83
-0.56

+2.39

Sortino ratioReturn per unit of downside risk
2.54
-0.51

+3.05

Omega ratioGain probability vs. loss probability

1.30

0.94

+0.37

Calmar ratioReturn relative to maximum drawdown

3.24

-0.77

+4.01

Martin ratioReturn relative to average drawdown

11.44

-1.13

+12.57

Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

IWM vs. UNG - Sharpe Ratio Comparison

The current IWM Sharpe Ratio is 1.83, which is higher than the UNG Sharpe Ratio of -0.56. The chart below compares the historical Sharpe Ratios of IWM and UNG, calculated using daily returns over the previous 12 months. A higher Sharpe Ratio indicates better risk-adjusted performance relative to the risk-free rate.

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Sharpe Ratios by Period

IWMUNGDifference

Sharpe Ratio (1Y)

Calculated over the trailing 1-year period

1.83

-0.56

+2.39

Sharpe Ratio (5Y)

Calculated over the trailing 5-year period

0.24

-0.37

+0.62

Sharpe Ratio (10Y)

Calculated over the trailing 10-year period

0.47

-0.39

+0.86

Sharpe Ratio (All Time)

Calculated using the full available price history

0.36

-0.57

+0.94

Drawdowns

IWM vs. UNG - Drawdown Comparison

The maximum IWM drawdown since its inception was -59.05%, smaller than the maximum UNG drawdown of -99.88%. Use the drawdown chart below to compare losses from any high point for IWM and UNG.

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Drawdown Indicators

IWMUNGDifference

Max Drawdown

Largest peak-to-trough decline

-59.05%

-99.88%

+40.83%

Max Drawdown (1Y)

Largest decline over 1 year

-11.03%

-43.86%

+32.83%

Max Drawdown (3Y)

Largest decline over 3 years

-27.50%

-68.16%

+40.66%

Max Drawdown (5Y)

Largest decline over 5 years

-31.91%

-92.49%

+60.58%

Max Drawdown (10Y)

Largest decline over 10 years

-41.13%

-93.55%

+52.42%

Current Drawdown

Current decline from peak

-2.71%

-99.86%

+97.15%

Average Drawdown

Average peak-to-trough decline

-10.76%

-89.97%

+79.21%

Ulcer Index

Depth and duration of drawdowns from previous peaks

3.11%

29.93%

-26.82%

Volatility

IWM vs. UNG - Volatility Comparison

The current volatility for iShares Russell 2000 ETF (IWM) is 6.52%, while United States Natural Gas Fund LP (UNG) has a volatility of 13.75%. This indicates that IWM experiences smaller price fluctuations and is considered to be less risky than UNG based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

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Volatility by Period

IWMUNGDifference

Volatility (1M)

Calculated over the trailing 1-month period

6.52%

13.75%

-7.23%

Volatility (6M)

Calculated over the trailing 6-month period

14.00%

53.10%

-39.10%

Volatility (1Y)

Calculated over the trailing 1-year period

19.53%

60.78%

-41.25%

Volatility (5Y)

Calculated over the trailing 5-year period, annualized

22.58%

64.14%

-41.56%

Volatility (10Y)

Calculated over the trailing 10-year period, annualized

23.07%

54.78%

-31.71%

IWM vs. UNG - Expense Ratio Comparison

IWM has a 0.19% expense ratio, which is lower than UNG's 1.28% expense ratio.

Dividends

IWM vs. UNG - Dividend Comparison

IWM's dividend yield for the trailing twelve months is around 0.89%, while UNG has not paid dividends to shareholders.

PositionTTM20252024202320222021202020192018201720162015
IWM
iShares Russell 2000 ETF		0.89%1.04%1.15%1.35%1.48%0.94%1.04%1.26%1.40%1.26%1.38%1.54%
UNG
United States Natural Gas Fund LP		0.00%0.00%0.00%0.00%0.00%0.00%0.00%0.00%0.00%0.00%0.00%0.00%

Frequently Asked Questions

IWM and UNG have a correlation of -0.27, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

UNG has higher volatility (13.75%) compared to IWM (6.52%). In terms of maximum drawdown, IWM dropped -59.05% vs UNG's -99.88%.

On 10-year performance, IWM leads with 10.78% vs -21.26% for UNG. On fees, IWM is cheaper at 0.19% per year. On volatility, IWM has been the lower-risk option at 6.52%. The better choice depends on whether you care most about return, fees, risk, or income.

Over the 10-year period, IWM has performed better with a 10.78% return vs -21.26%. Past performance does not guarantee future results, so compare this with risk, fees, and fund exposure.

IWM is cheaper with a 0.19% expense ratio, compared with 1.28% for UNG.

IWM has the higher dividend yield at 0.89%, compared with 0.00% for UNG.

IWM is categorized as Small Cap Blend Equities, while UNG is Oil & Gas. IWM tracks Russell 2000 Index, while UNG tracks Front Month Natural Gas. They also come from different issuers: iShares and Concierge Technologies. Their fees differ too: 0.19% for IWM and 1.28% for UNG.

IWM currently has the higher Sharpe Ratio (1.83 vs -0.56), meaning it's delivered slightly more return per unit of risk over the trailing 12 months. However, this ranking shifts over time - use the Risk/Return Score above for a more comprehensive view that combines Sharpe, Sortino, and other measures used by quantitative funds.

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